Spectrum for promoting growth of cannabis plants

ABSTRACT

A spectrum for promoting growth of  cannabis  plants. The spectrum comprises adding an irradiation of red light with peak wavelength at 655-690 nm into an indoor growing environment of  cannabis  to improve the levels of THC and CBD, the cannabinoid substances in  cannabis . A ratio of photon number of the red light to the photon number of the entire light source is in a range from 40% to 70%. While maintaining the light intensity and other growth conditions, the yields and levels of THC and CBD, the cannabinoid substances in  cannabis , can be increased by up to 32.48%.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of PCT patent Application No.PCT/CN2019/106427, filed on Sep. 18, 2019, entitled “Light RegulationMethod for Promoting Accumulation of Secondary Metabolites in CannabisPlants”, which claims priority of U.S. patent application Ser. No.16/446,602, filed on Jun. 19, 2019, in the USPTO, the entire content ofwhich are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The subject matter herein relates to a technical filed of medicinalplants, and in particularly relates to a spectrum for promoting growthof cannabis plants.

BACKGROUND

Cannabis (Cannabis sativa L.) is an annual erect herb. The main activeingredient in cannabis plants is cannabinoids. Currently, over 70 kindsof natural cannabinoids are found, which are mainly used in some nervoussystem diseases, such as multiple sclerosis, motor neuropathy, chronicintractable pain, a drug-induced vomiting. Tetrahydrocannabinol (THC)and cannabidiol (CBD) are the main active ingredients. The level of CBDis a key medicinal quality indicator of industrial hemp mosaic. As anon-psychoactive compound, CBD has excellent tolerance and above-averagesafety, and is widely used in the field of medical research. CBD exertsanalgesic and anti-inflammatory effects through dual inhibition ofcyclooxygenase and lipoxygenase. It also has potential medical value inthe treatment of schizophrenia, Alzheimer's disease and epilepsy. Italso has a good intervention effect for drug-induced mental dependencesuch as morphine, cocaine, alcohol or the like. Tetrahydrocannabinol(THC) is a psychoactive cannabinoid. It is usually administered orallyor inhaled. After being absorbed, it circulates through the blood tovarious organs and tissues, thereby exerting effects includinganalgesia, anti-inflammatory, immune regulation, anti-cancer, etc. Thelevels of THC and CBD are one of the important indicators ofhigh-quality medicinal cannabis. Medicinal cannabis with high levels ofTHC and CBD has higher medicinal value and economic benefits in thecannabinoid extraction and processing industry. Therefore, the cannabiscultivation and regulation technology for obtaining high levels ofmedicinal ingredients has important application value. Accordingly, thecultivation technology of medicinal cannabis plants with high levels ofCBD and THC has become a difficult point that needs to be solvedurgently.

Indoor cultivation of cannabis can obtain plant raw materials withstable level and yield of medicinal ingredients in full years withoutbeing affected by seasons, because the indoor cultivation of cannabishas stable environmental factors including light, temperature, humidity,nutrition and the like required for growth. Light is one of the mostrelevant environmental factors influencing plant behavior. It is notonly the basic energy source for photosynthesis, but also an importantregulator of plant growth and development, which plays a significantrole in plants' morphogenesis, reproductive development, and regulationof secondary metabolites. Cannabis is a light-loving and short-dayplant, which is sensitive to light. It is an important technical meansto improve the secondary metabolites for medicinal components byadjusting the light quality ratio of the light environment in the growthof cannabis. The way to adjust the light quality ratio of the lightenvironment is feasible and simple for implementation. It will become aneffective technology for producing medicinal cannabis with high levelsof CBD and THC and provide a reliable way to provide high-quality rawmaterials for producing cannabinoid.

At present, high-pressure sodium lamps (HPS), metal halide lamps (MH),and light-emitting diode lights (LED) are mainly used to provide a lightenvironment for indoor cannabis cultivation. HPS and MH are limited bytheir spectral design, and the achievable spectral energy distributionis limited. LED lights have the characteristics of narrow half-heightand flexible spectral design, which have been widely studied. It hasbecome an important research goal of high-quality and high-efficiencycultivation and production of medical cannabis to explore thecultivation methods for promoting accumulation of CBD and THC. However,in the LED light spectrum matching method that promotes accumulation ofsecondary metabolites in plants, it has not yet disclosed how to promotethe indoor cultivation and growth of cannabis plants to achieve a bettereffect of promoting accumulation of levels of CBD and THC, secondarymetabolites in cannabis.

SUMMARY

With respect to the background, one object of the present disclosure isto provide a spectrum for promoting growth of cannabis plants byregulating a growing environment of the cannabis.

Specifically, the object of the present disclosure is achieved by thefollowing embodiments.

A spectrum for promoting growth of cannabis plants is provided. Morespecifically, an irradiation of red light is added into an indoorgrowing environment of cannabis to improving the levels and yields ofTHC and CBD, cannabinoid substances in the cannabis; wherein the redlight has a peak wavelength at 655-690 nm.

In some embodiments, the step of adding the irradiation of red lighthaving the peak wavelength at 655-690 nm comprises a combinedirradiation with other wavelength bands or independent irradiation.

In some embodiments, in the combined irradiation with other wavelengthbands, a ratio of the photon number of the red light to the photonnumber of the entire light source is 40-70%.

In some preferred embodiments, the ratio of the photon number of the redlight to the photon number of the entire light source is 52-65%.

In some embodiments, the light source used in the indoor growingenvironment of cannabis is a LED light source.

In some embodiments, the LED light source is composed of 11.11-22.22%blue light, 40-70% red light, and 18.89-37.78% green light.

In some embodiments, the blue light has a peak wavelength at 440-460 nm,the red light has a peak wavelength at 660-685 nm, and the green lighthas a peak wavelength at 505-526 nm.

In some embodiments, the peak wavelength of the red light, preferably,lies at 680 nm.

In some embodiments, a ratio of the photon number of the blue light tothe photon number of the red light is 1:4.

In some embodiments, the LED light source is realized directly by a LEDchip or by using the LED chip to excite a phosphor material.

In some embodiments, an initial light intensity is 80 μmol/m² s, amaximum light intensity is 1000 μmol/m² s, and a photoperiod is 10-16h/d.

Compared with the prior art, the present disclosure has the followingadvantages.

The present disclosure provides a method for promoting accumulation ofTHC and CBD, secondary metabolites in cannabis. By introducing anirradiation of red light into the indoor growing environment of thecannabis to improve the levels and yields of THC and CBD, secondarymetabolites in cannabis; wherein the red light has a peak wavelength at655-690 nm. While maintaining the light intensity and other growthconditions, the yields and/or levels of THC and CBD, secondarymetabolites in cannabis, can be increased by at least to 32.48%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a spectral distribution diagram from a LED light source whichis realized directly by a LED chip according to the present disclosure.

FIG. 2 is a spectral distribution diagram from a LED light source whichis realized by using the LED chip to excite a phosphor materialaccording to the present disclosure.

FIG. 3 is a spectral distribution diagram of red-light waveband from aLED light source which is realized by using the LED chip.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure will be further described in detail below withreference to the drawings and specific embodiments, in order to betterunderstand the objective, the technical solution and the advantage ofthe present disclosure. It should be understood that the specificembodiments described herein are merely illustrative and are notintended to limit the scope of the disclosure.

In the early stage of treatment to cannabis seedling, top branches ofstrong cannabis mother plant are selected as stem cuttings for plantcutting, or cannabis seeds are selected for sowing. The seedling stageis about 2 weeks. The cannabis seedlings with good rooting conditionsare transplanted into the substrate or rock wool for the vegetativegrowth phase (the vegetative growth stage is about 4 weeks). Each rockwool block has 1 plant, and a density for the transplanted cannabisseedlings is 9 plants/m². The plant is topped when the plant is about 20cm high for triggering the growth of side branches. After the vegetativegrowth stage is finished, the plant is moved to the flower promotionstage for flower promotion treatment. The planting density of the plantin the flower promotion stage is 4-6 plants/m². A distinguishment to themale and female flowers is required. The male flowers will be removed,and the female plants will be cultivated. The cultivation environment isset to have a day and night temperature at 24-26° C./21-22° C., humidityat 60-70%, CO₂ concentration at 10000 ppm. Throughout the growthprocess, the LED light source directly realized by the LED chip is anartificial light source. The spectrum distribution diagram directlyrealized by the LED chip is shown in FIG. 1. The LED light source asshown provides a light environment for the growth of cannabis. Aninitial light intensity is set to 80-100 μmol/m² s. As the plant heightincreases, the light intensity may reach 500-1000 μmol/m² s in the latestage, and the photoperiod is 10-16 h/d. After 7-9 weeks of growth atthe flowering stage, the accumulation of levels and yields of THC andCBD, the cannabinoid substances in plants, would be promoted.

Embodiment 1

Top branches of strong cannabis mother plant are selected as stemcuttings for plant cutting. After the plant cutting is finished (theplant cutting stage is about 2 weeks), the cannabis seedlings with goodrooting conditions are transplanted into the rock wool or the substratefor the vegetative growth phase (the vegetative growth stage is about 4weeks). Each rock wool block has 1 plant, and a density for thetransplanted cannabis seedlings is 9 plants/m². The plant is topped whenthe plant is about 20 cm high for triggering the growth of sidebranches. After the vegetative growth stage is finished, the plant ismoved to the flower promotion stage for flower promotion treatment. Theplanting density of the plant in the flower promotion stage is 4plants/m². A distinguishment to the male and female flowers is required.The male flowers are removed, and the female plants is cultivated asbefore. The cultivation environment is set to have a day and nighttemperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂concentration at 10000 ppm. Throughout the growth process, the LED lightsource is used to provide a light environment for the growth of theplant. An initial light intensity is set to 100 μmol/m² s. As the plantheight increases, the light intensity reaches 550 μmol/m² s in the latestage, and the photoperiod is 12 h/d. Four control examples 1-4 areprovided by using the blue LED light source having peak wavelength at450 nm, the red LED light source having peak wavelength at 630 nm, thered LED light source having peak wavelength at 710 nm, and the red LEDlight source having peak wavelength at 730 nm, respectively. Sixexperimental examples 1-6 are provided by using the red LED light sourcehaving peak wavelength at 655 nm, 660 nm, 670 nm, 680 nm, 685 nm, 690nm, respectively. When harvesting, the levels of CBD and THC in thecannabis plants are determined, and the dry weight of the inflorescenceis collected at the same time to calculate the yields of CBD and THC perplant. The experimental results are shown in Table 1.

TABLE 1 Peak CBD THC Inflorescence CBD THC Ind. WL/ level level DW yieldyield Irradiation nm (%) (%) g/plant g/plant g/plant Cont. Ex. 1 4505.27 4.58 58.27 2.91 3.07 Cont. Ex. 2 630 5.42 4.60 83.14 4.51 3.82Cont. Ex. 3 710 4.74 3.89 31.15 1.48 1.21 Cont. Ex. 4 730 4.52 3.5724.84 1.12 0.89 Exptl. Ex. 1 655 5.69 4.80 83.09 4.74 3.98 Exptl. Ex. 2660 5.77 4.87 82.45 4.76 4.02 Exptl. Ex. 3 670 6.05 5.04 83.02 5.02 4.18Exptl. Ex. 4 680 6.14 5.24 83.78 5.14 4.39 Exptl. Ex. 5 685 6.06 5.1184.67 5.13 4.33 Exptl. Ex. 6 690 5.80 4.86 79.57 4.62 3.87

The results suggest that, compared with control examples 1-4, the redlight source in experimental examples 1-6 may greatly improve the levelsof THC and CBD in the cannabis. Besides, compared with control example1, the red light having peak wavelength at 680 nm is the most effectiveone which improves the levels of THC and CBD up to 16.51%. At the sametime, the red light sources in experimental examples 1-6 are also goodfor the accumulation of inflorescence weight in the cannabis, andimproving the yields of CBD and THC per plant.

Embodiment 2

Top branches of strong cannabis mother plant are selected as stemcuttings for plant cutting. After the plant cutting is finished (theplant cutting stage is about 2 weeks), the cannabis seedlings with goodrooting conditions are transplanted into the rock wool or the substratefor the vegetative growth phase (the vegetative growth stage is about 4weeks). Each rock wool block has 1 plant, and a density for thetransplanted cannabis seedlings is 9 plants/m². The plant is topped whenthe plant is about 20 cm high for triggering the growth of sidebranches. After the vegetative growth stage is finished, the plant ismoved to the flower promotion stage for flower promotion treatment. Theplanting density of the plant in the flower promotion stage is 4plants/m². A distinguishment to the male and female flowers is required.The male flowers are removed, and the female plants is cultivated asbefore. The cultivation environment is set to have a day and nighttemperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂concentration at 10000 ppm. Throughout the growth process, the LED lightsource is used to provide a light environment for the growth of theplant. An initial light intensity is set to 100 μmol/m² s. As the plantheight increases, the light intensity reaches 750 μmol/m² s in the latestage, and the photoperiod is 12 h/d. Spectrum of combined light sourceare used in four control examples (Cont. Ex. 5-8 as shown in Table 2)and five experimental examples (Exptl. Ex. 7-11 as shown in Table 2).The peak wavelength of blue lights in the spectrum in both controlexamples and experimental examples lie at 450 nm, while the green lightat 526 nm and the red light at 660 nm. A ratio of the green light to theblue light is fixed at 1.7. Different ratios of red light are providedin control examples 5-8 and experimental examples 7-11. When harvesting,the levels of THC and CBD in the cannabis are determined, and the dryweight of the inflorescence is collected at the same time to calculatethe yields of THC and CBD per single plant. The experimental results areshown in Table 2.

TABLE 2 Spectral composition and Peak characteristics X1, X2, X3, Ratioof Ratio of Ratio of 400-499 500-599 600-780 nm nm nm photons photonsphotons to to to Biological indicators 380-780 380-780 380-780 Inflores-nm light nm light nm light CBD THC cence CBD THC source source sourcelevel level DW yield yield SN (%) (%) (%) (%) (%) g/plant g/plantg/plant Cont. 31.48 53.52 15 9.42 3.19 120.37 11.34 3.84 Ex. 5 Cont.25.92 44.08 30 9.65 3.30 124.49 12.01 4.11 Ex. 6 Cont. 7.41 12.59 809.56 3.26 123.58 11.81 4.03 Ex. 7 Cont. 3.70 6.30 90 9.03 3.08 118.3510.69 3.65 Ex. 8 Exptl. 22.22 37.78 40 10.89 3.61 138.26 15.06 4.99 Ex.7 Exptl. 17.78 30.22 52 11.21 3.74 139.12 15.60 5.20 Ex. 8 Exptl. 15.5626.44 58 11.41 3.82 143.25 16.34 5.47 Ex. 9 Exptl. 12.95 22.05 65 11.233.72 145.69 16.36 5.42 Ex. 10 Exptl. 11.11 18.89 70 10.72 3.56 140.2115.03 4.99 Ex. 11

The results suggest that, compared with control examples 5-8, theexperimental examples 7-11, which regulates the ratio of red light tothe light source in a range of 40-70%, may greatly increase the levelsof THC and CBD in the cannabis. Compared with control example 5, thelevels of CBD and THC in experimental example 9 have been increased by21.13% and 19.75%, respectively. At the same time, it is beneficial toimprove the accumulation of inflorescence weight of cannabis andincrease the yields of CBD and THC per plant by adding into thecombination of blue light and green light with different ratios of redlight.

Embodiment 3

Top branches of strong cannabis mother plant are selected as stemcuttings for plant cutting. After the plant cutting is finished (theplant cutting stage is about 2 weeks), the cannabis seedlings with goodrooting conditions are transplanted into the rock wool or the substratefor the vegetative growth phase (the vegetative growth stage is about 4weeks). Each rock wool block has 1 plant, and a density for thetransplanted cannabis seedlings is 9 plants/m². The plant is topped whenthe plant is about 20 cm high for triggering the growth of sidebranches. After the vegetative growth stage is finished, the plant ismoved to the flower promotion stage for flower promotion treatment. Theplanting density of the plant in the flower promotion stage is 4plants/m². A distinguishment to the male and female flowers is required.The male flowers are removed, and the female plants is cultivated asbefore. The cultivation environment is set to have a day and nighttemperature at 24-26° C./21-22° C., humidity at 60-70%, CO₂concentration at 10000 ppm. Throughout the growth process, the LED lightsource is used to provide a light environment for the growth of theplant. An initial light intensity is set to 100 μmol/m² s. As the plantheight increases, the light intensity reaches 800 μmol/m² s in the latestage, and the photoperiod is 12 h/d. A light source composed of 15%blue light, 25% green light and 60% red light is provided as theexperimental light source. The blue light has a peak wavelength at 450nm, the green light has a peak wavelength at 520 nm. On this basis, sameratio of red lights having different peak wavelengths are introduced toform control examples 9-11 and experimental examples 12-17 (as shown inTable 3). Additionally, the ratio of photon numbers between the redlight (600-780 nm) and the blue light (400-499 nm) is 4:1. Whenharvesting, the levels of CBD and THC in the cannabis are determined,and the dry weight of the inflorescence is collected at the same time tocalculate the yields of CBD and THC per plant. The experimental resultsare shown in Table 3.

TABLE 3 Spectral composition and Peak characteristics X1, X2, X3, Ratioof Ratio of Ratio of 400-499 500-599 600-780 nm nm nm photons photonsphotons to to to Biological indicators 380-780 380-780 380-780 Inflores-nm light nm light nm light Red CBD THC cence CBD THC source sourcesource peak level level DW yield yield SN (%) (%) (%) WL (%) (%) g/plantg/plant g/plant Cont. 15 25 60 630 10.65 3.65 136.49 14.54 4.98 Ex. 9Cont. 15 25 60 710 9.12 3.15 119.46 10.89 3.76 Ex. 10 Cont. 15 25 60 7308.56 3.04 112.58 9.64 3.42 Ex. 11 Cont. 15 25 60 655 10.93 3.76 137.5615.04 5.17 Ex. 12 Exptl. 15 25 60 660 11.01 3.80 136.25 15.00 5.18 Ex.13 Exptl. 15 25 60 670 11.15 3.83 138.65 15.46 5.31 Ex. 14 Exptl. 15 2560 680 11.34 3.91 139.24 15.79 5.44 Ex. 15 Exptl. 15 25 60 685 11.283.84 138.62 15.64 5.32 Ex. 16 Exptl. 15 25 60 690 10.98 3.78 139.5715.32 5.28 Ex. 17

The results suggest that the obtained CBD and THC levels will beverified when the wavelength of red light is changed in the combinedirradiation of red-blue-green light. Compared with control examples9-11, the light sources in experimental examples 12-17 will improve, ina certain, the levels of THC and CBD in cannabis. Compared with controlexample 11, the light source in experimental example 15 improves thelevels of CBD and THC up to 32.48% and 28.62%, respectively. At the sametime, the addition of different ratios of red light will be beneficialto improve the accumulation of inflorescence weight of cannabis andincrease the yields of CBD and THC per plant.

In summary, plants experience different light qualities throughphotoreceptors such as phytochromes and cryptochromes. The lightabsorbed by plants is concentrated in the visible part of the wavelengthrange of 380 to 780 nm. Red light accounts for about 85% of the absorbedphysiological radiation light energy, and blue light accounts for about12%. Therefore, the red light and blue light are essential lightqualities for plant growth. The red light is mainly used to generateassimilate and accumulate biomass, and the blue light is a necessarycondition for chlorophyll synthesis and chloroplast formation. The bluelight affects the morphology of plants by controlling the stomata shape.At the same time, the blue light can also promote the accumulation ofsecondary metabolites in plants. Green light has always been acontroversial light quality. Some scholars believe that it will inhibitthe growth of plants, cause the plants to be short and reduce the yieldof leafy vegetables. In the present disclosure, under the proof of theabove-mentioned embodiments, it is beneficial for promoting accumulationof levels and yields of CBD and THC, the cannabinoid substances incannabis, by adding an irradiation of red light with peak wavelength at655-590 nm into the indoor growing environment of cannabis andmaintaining the ratio of photon number of the red light (600-780 nm) tothe photon number of the entire light source (380-780 nm) in a range of40-70%. Therefore, different plants may have different optimal spectralformula during growth. The special spectral formula for cannabis asprovided may enable the cannabis to accumulate and synthesize more THCand CBD, secondary metabolites in the cannabis, during the industrialcultivation.

It should be noted that the aforementioned embodiments are merelypreferred embodiments of the present disclosure, and those embodimentsare not to be deemed as limiting the scope of the invention. The scopeof the disclosure should be limited by the by the scope of the claims.It will be apparent to those skilled in the art that other modificationsand changes may be made without departing from the spirit and scope ofthe disclosure.

What is claimed is:
 1. A spectrum for promoting growth of cannabisplants, comprising: adding an irradiation of red light into an indoorgrowing environment of cannabis to improve accumulation of levels andyields of tetrahydrocannabinol (THC) and cannabidiol (CBD) in thecannabis; wherein the red light has a peak wavelength at 655-690 nm. 2.The spectrum of claim 1, the step of adding the irradiation of red lighthaving the peak wavelength at 655-690 nm into an indoor growingenvironment of cannabis comprises a combined irradiation with otherwavelength bands or an independent irradiation.
 3. The spectrum of claim2, wherein the in the combined irradiation with other wavelength bands,a ratio of the photon number of the red light to the photon number ofthe entire light source is 40-70%.
 4. The spectrum of claim 3, whereinthe ratio of the photon number of the red light to the photon number ofthe entire light source is 52-65%.
 5. The spectrum of claim 2, whereinthe light source used in the indoor growing environment of cannabis is aLED light source.
 6. The spectrum of claim 4, wherein the LED lightsource is composed of 11.11-22.22% blue light, 40-70% red light, and18.89-37.78% green light.
 7. The spectrum of claim 4, wherein the bluelight has a peak wavelength at 440-460 nm, the red light has a peakwavelength at 660-685 nm, and the green light has a peak wavelength at505-526 nm.
 8. The spectrum of claim 7, wherein the peak wavelength ofthe red light lies at 680 nm.
 9. The spectrum of claim 6, wherein aratio of the photon number of the blue light to the photon number of thered light is 1:4.
 10. The spectrum of claim 3, wherein the LED lightsource is realized directly by a LED chip or by using the LED chip toexcite a phosphor material.
 11. The spectrum of claim 3, wherein aninitial light intensity is 80 μmol/m² s, a maximum light intensity is1000 μmol/m² s, and a photoperiod is 10-16 h/d.
 12. The spectrum ofclaim 1, wherein the light source used in the indoor growing environmentof cannabis is a LED light source.
 13. The spectrum of claim 5, whereina ratio of the red light in the LED light source is 52-65%.
 14. Thespectrum of claim 6, wherein a ratio of the red light in the LED lightsource is 52-65%.